The NIDDK Liver Transplantation Database (LTD) is a multicenter registry of more than 1500 consecutive candidates for liver transplantation (LT), recruited between 1990 and 1994, by three major liver transplant centers in the United States. As such, it is the only scientifically designed and implemented multicenter study from which the recent experience of a large cohort of LT candidates and recipients in this country can be rigorously analyzed. The effort to build this detailed and high quality resource was carried out under a 7-year NIDDK contract which ends in December 1997. Valuable information collected in this study includes clinical and laboratory data collected by protocol and at a time of events, and it is enriched with protocol biopsies from a high proportion of recipients, a bank of serial serum specimens, and a virtual tissue bank. Since the current contract only provided for follow-up of 3 years on average, the range of topics that could be investigated, using this comprehensive data base, is limited. The current plan is to continue the follow-up of the cohort of transplant recipients for another 5 years through the next phase of the post-transplantation period, when recurrence of the original disease and long-term adverse effects of immunosuppression and re-transplantation are most likely to occur. Thus, the Coordinating Center, with the support of the investigators of the three LTD clinical centers, will be able to obtain complete follow-up for an average of 10 years (8-12 years) to observe the information recorded in the study before, during an dafter transplantation. The proposed effort is expected to yield results of great scientific and clinical importance which could directly influence future transplant candidate selection and post-transplantation patient management.